SUPPLEMENTARY INFORMATION:

Background

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to all RRD Model Trent7000-72 and Trent7000-72C engines. The NPRM was published in the Federal Register on May 20, 2026 (91 FR 29391). The NPRM was prompted by AD 2024-0029, dated January 29, 2024, issued by EASA, which is the Technical Agent for the Member States of the European Union (EASA AD 2024-0029) (also referred to as the MCAI). The MCAI states that there have been reports of engine IFSDs prompted by low oil pressure indications. An investigation revealed that these events were caused by early-life failure of the internal eccentric ring/gerotor in certain affected lubrication/scavenge oil pumps due to eccentric contact between the ring and gerotor causing wear on the components. To address this potential unsafe condition, the manufacturer published service material that provides installation criteria for the affected oil pumps.

In the NPRM, the FAA proposed to require prohibiting the installation of certain lubrication/scavenge pumps unless certain installation criteria are met. The FAA is issuing this AD to address the unsafe condition on these products.

You may examine the MCAI in the AD docket at regulations.gov under Docket No. FAA-2026-4640.

Discussion of Final Airworthiness Directive

Comments

The FAA received comments from two commenters. Commenters included the Air Line Pilots Association, International (ALPA) and Delta Air Lines, Inc (DAL). ALPA supported the NPRM without change. The following presents the comments received on the NPRM and the FAA's response to each comment.

Request To Prohibit Operation of an Engine With an Affected Part

DAL requested that the FAA revise paragraph (h)(2) of the proposed AD to prohibit the operation of an affected part unless the installation criteria defined in RRD Non-Modification Service Bulletin (NMSB) TRENT 1000 79-AK868, Revision 3, dated December 11, 2023 (RRD NMSB TRENT 1000 79-AK868, Revision 3) are met. DAL stated that two of the installation criteria defined in RRD NMSB TRENT 1000 79-AK868, Revision 3 require knowledge of the cycles since repair (CSR), cycles since overhaul (CSO), and cycles since new (CSN) of the oil pump on the opposite engine. DAL noted that during installation of an affected part on a spare engine or during an engine shop visit for maintenance, it is not always known which aircraft an engine will be installed on. DAL further noted that in such cases, it is impossible to determine the CSR, CSO, or CSN of the oil pump on the opposite engine, and the installation criteria defined in RRD NMSB TRENT 1000 79-AK868, Revision 3 cannot be complied with prior to pump installation.

The FAA disagrees with the request. The FAA infers that the intent of the request is to prohibit the operation of an engine having an affected part installed unless the installation criteria from RRD NMSB TRENT 1000 79-AK868, Revision 3, are met. The FAA clarifies that this operation prohibition is already required by the AD because 14 CFR 39.7 specifies that once an AD is issued, no person may operate a product to which the AD applies except in accordance with the requirements of that AD. The intent of this AD is to prevent the installation of affected parts unless they meet the installation criteria from RRD NMSB TRENT 1000 79-AK868, Revision 3. The FAA did not change this AD as a result of this comment.

Request To Remove Documentation Requirement

DAL requested that the FAA revise paragraph (h) of the proposed AD to state that documentation of the accomplishment of RRD NMSB TRENT 79-AK868, Revision 3, is not required. Delta noted that RRD NMSB TRENT 79-AK868, Revision 3, requires operators to record accomplishment of the completed work in the engine logbook. DAL further noted that they do not use engine logbooks to document engine maintenance performed while the engine is installed on an airplane and should be permitted to incorporate the installation criteria into the DAL Continued Airworthiness Maintenance Program instead. DAL stated that requiring a logbook entry creates unnecessary administrative burden to operators.

The FAA agrees to clarify. An operator may record the accomplishment of RRD NMSB TRENT 79-AK868, Revision 3, in a document or system other than an engine logbook, or an equivalent record, including their continuing airworthiness maintenance program. The FAA did not change this AD as a result of this comment.

Conclusion

These products have been approved by the civil aviation authority of another country and are approved for operation in the United States. Pursuant to the FAA's bilateral agreement with this State of Design Authority, that authority has notified the FAA of the unsafe condition described in the MCAI referenced above. The FAA reviewed the relevant data, considered any comments received, and determined that air safety requires adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products. Except for minor editorial changes, this AD is adopted as proposed in the NPRM. None of the changes will increase the economic burden on any operator.

Material Incorporated by Reference Under 1 CFR Part 51

The FAA reviewed EASA AD 2024-0029, which specifies installation criteria for affected oil pumps each time an affected part is installed or reinstalled on an engine. This material is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

Costs of Compliance

The FAA estimates that this AD affects 98 engines installed on airplanes of U.S. registry.

The FAA estimates the following costs to comply with this AD: ( printed page 55456)

The FAA estimates the following costs to do any necessary screening tests that would be required based on the results of the installation criteria verification. The agency has no way of determining the number of engines that might need these screening tests:

Authority for this Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority.

The FAA is issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: General requirements. Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

This AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Will not affect intrastate aviation in Alaska, and

(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

The Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: